Disable XvMC on 915G/GM in KMS

These chips require physical address for XvMC surface, which
is not available in KMS case. Instead of crashing X, disable it now.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

src/i830_hwmc.c

@@ -55,6 +55,10 @@ Bool intel_xvmc_probe(ScrnInfoPtr pScrn)
     if (!pI830->XvMCEnabled)
 	return FALSE;
 
+    if (pI830->use_drm_mode &&
+	    (IS_I915G(pI830) || IS_I915GM(pI830)))
+	return FALSE;
+
     if (IS_I9XX(pI830)) {
 	if (IS_I915(pI830))
 	    ret = intel_xvmc_set_driver(&i915_xvmc_driver);